1. Field of the Invention
The present invention relates to a portable videophone unit which has a camera and a monitor, and which can transmit and receive images and sound using a wireless public network.
2. Description of Related Art
Portable videophone units have been hitherto known which have a camera and a monitor as input and output parts for images and a microphone and a speaker as input and output parts for sound, and which encode images and sound input by the camera and the microphone, respectively, and transmit the encoded images and sound to an opposite party via a public network while receiving encoded images and sound sent by the opposite party and decoding them into images, which are displayed by the monitor, and sound, which is output from the speaker, whereby the user can have a conversation while seeing images from the opposite party.
On the other hand, as automatic response functions of telephone sets, the following have hitherto been known.
(1) A function of a portable telephone unit by which when an incoming call is detected, the portable telephone unit automatically proceeds to an off-hook status and receives a message sent by the opposite party.
(2) A function by which the telephone set automatically responds to the calling party on behalf of the user and records a message when the user is not by the telephone or the user cannot answer the telephone, such as when the user is having a meal at a quiet restaurant, when the user is in a concert hall, or when the user is attending an important meeting. (so called “answering system”)
(3) A function, which is often found on automobile telephone sets, by which when an incoming signal is detected, the telephone set automatically receives the signal, and communication between two parties is made possible.
According to this function, the telephone set proceeds to an off-hook status without the user touching it, and conversation during driving is made possible.
(4) A basic function of facsimile machines, by which when an incoming signal is detected, the telephone line is connected to receive data.
However, none of the above functions realizes smooth two-way communication using images and sound after automatic response.
Moreover, for conventional automatic response functions there is a premise that the telephone set responds to all incoming calls from unspecified general calling parties, and such conventional automatic response functions cannot satisfy users' desire to permit automatic response only to incoming calls from particular calling parties.